(a) Field of the Invention
The present invention relates to a compact photographic camera lens system using 35 mm-size film designed for a field angle of at least 60.degree. and an F number of 4.5, and so adapted as to comprise a small number of lens components, have a short overall length and be favorably corrected in various aberrations by using certain lens components having aspherical surfaces.
(b) Description of the Prior Art
Most of compact photographic camera lens systems using Leica size film are generally designed for a field angle around 63.degree.. In order to design lens systems of this class as very compact systems having telephoto ratios of 1.0 and lower, it is necessary to locate the rear principal point of the entire lens system before the first lens surface. For the purpose of satisfying this requirement, it is considered to adopt a lens type generally used as telephoto lenses comprising a front lens group designed as a converging lens system and a rear lens group designed as a diverging lens system within a single lens system.
In case of the general telephoto type lens systems, however, field angles requiring good image quality are far narrower than 63.degree.. In order to design the lens system mentioned as the object of the present invention, it is therefore required to favorably correct aberrations over a wide range up to a field angle of 63.degree.. That is to say, correction of offaxial aberrations poses an important problem.